So, you are now the leader of a SQL Server based project and this is your first one, perhaps migrating from Access. Or maybe you have performance problems with your SQL Server and don't know what to do next. Or maybe you simply want to know of some design guidelines for solutions using SQL Server and designing Database Access Layers (DAL): this article is for you.

http://www.codeproject.com/KB/database/sqldodont.aspx

This is a huge list of whitepapers for SQL Server 2005.

http://www.sqlskills.com/whitepapers.asp